Waves and Vibrations Cool Kids Video Let Us

Waves and Vibrations Cool Kids Video Let Us Entertain You! 1

What do you know about waves? p 85 ©Write down 5 things that you know about waves in your notebook. Be specific and write complete sentences! ©Now write 3 questions that you have about waves ©Share out 2

Waves are everywhere in nature ©Sound waves, ©visible light waves, ©radio waves, ©microwaves, ©water waves, ©sine waves, ©telephone chord waves, ©stadium waves, ©earthquake waves, ©waves on a string, ©slinky waves 3

Big idea – a method of communication is a means by which information or ideas can be transferred from your mind to someone else’s (information like how to build a doghouse) © Fill in the chart with the following methods of communication and give evidence for your placement: speaking/listening, writing/reading, television, morse code, braille, texting, email Methods of communication that involve waves Methods of communication that DO NOT involve waves © How are each of the 5 senses activated by wave 4 stimuli? p 85

Bell Jar p 85 In Space No One Can Hear You Scream… ©Describe the apparatus ©Describe what happens to the noise when the vacuum pump is turned on. ©Describe what happens as air reenters the bell jar. ©What conclusion can be drawn about the slogan for Alien based on what we observed here? 5

See Sounds p 85 ©Make some noise! ©Record what you notice about the wave forms ©The up/down direction is Amplitude. Describe when the amplitude gets bigger or smaller. ©The left/right direction is wave length. Describe how to make the wavelength change. 6

Rank the sounds © from highest (pitch) frequency to lowest… © from loudest to quietest… © What does high frequency look like? © What does LOUD look like? p 86 7

Correct order 8

Investigation #1 (p 484 -486) What is the effect of string length and tension on pitch? ©Record your observations and answer lab questions (steps 1 -6) in your notebook 9 ©Get a stamp when you are done P 87

Wave model physics DQ: What properties do all sound waves exhibit? p 88 1. ) The pitch of a sound corresponds to the frequency of vibration of the object producing the sound. The higher the pitch, the higher the frequency. 2. ) Decreasing the length of a vibrating string increases the pitch (frequency). 3. ) Increasing the tension on the string also increases the pitch (frequency) 10

Finish Invest #1 – Sounds in Vibrating Strings Get a stamp when finished P 87 ©READ p 486 -487 and answer CU (p 487) 1 -4 P 89 ©Answer Pto. Go (p 490) 1 -7 ©Get another stamp 11

What is a wave? p 90 ©a wave is a oscillation that travels through a medium from one location to another. There are no sound waves that can travel through empty space. ©a wave is the motion of a disturbance ©Transfer of energy (not matter) ©Waves have amplitude, wavelength, frequency, crests and troughs 12

Wave Basics p 90 13

p 90 ©Wave Period is the time it takes 1 wavelength to pass ©Wave frequency is how many waves pass in one time period 14

Amplitude and Wavelength p 90 1. ) How does the sound change when the amplitude is changed? 2. ) How does the sound change when the wavelength is changed? 15

Investigation #2 p 492 -498 Distinguish between longitudinal and transverse waves p 91 ©Part A: Stadium wave ©Make a stadium wave with your class ©A 1. Which direction did the wave move? ©A 2. Which way did you move? ©A 3. How did the wave move without you moving in that direction? ©A 4. What variables can you change in your class wave (describe at least 3)? 16

How many waves? p 91 ©Use a slinky to makes waves. How many different kinds of waves can you make with a slinky? Draw each kind in your notebook… ©You have only 10 minutes… 17

Part B: Transverse waves and standing waves p 91 ©B 1. Which direction did the wave move? ©B 2. Which way did the tape in the middle of the slinky move? ©B 3. Describe a transverse wave. ©B 4. What word best describes a transverse wave? 18

Part C: Longitudinal waves p 91 ©C 1. Which direction did the wave move? ©C 2. Which way did the tape in the middle of the slinky move? ©C 3. Describe a longitudinal wave. ©C 4. What word best describes a longitudinal wave? ©C 5. What kind of wave is a stadium wave? Use slinky evidence to support your answer. 19

Wave vocab P 93 ©Define each vocabulary word using your own words (do not copy the book definition) and draw a picture to show the meaning of the word Vibrate pitch amplitude crest/peak trough wavelength node antinode periodic wave standing wave medium frequency period Transverse wave longitudinal wave 20

Finish ©Part D: Wave Interference ( wavey sim worksheet…use phet wave interference sim) p 92 ©Read p 498 -502. Answer Cu (p 502) 1 -3 ©Get a stamp when you finish ©Vocab Active Physics p 498 -501. Define in 21 your own words and draw a picture p 93

Directions: ppt slides 22 -45 highlight or circle gold words on ppt watch all animations click/watch all underlined links answer any questions get each page stamped when finished P 94 -95 © Your wave model (what do you know about waves…list at least 5) © © © Get stamps when finished and finish vocab 22

Slinky Wave ©Let’s use a slinky wave as an example. ©When the slinky is stretched from end to end and is held at rest, it assumes a natural position known as the equilibrium or rest position. ©To introduce a wave here we must first create a disturbance. ©We must move a particle away from its rest position. 23

Slinky Wave © One way to do this is to push the slinky forward © the beginning of the slinky moves away from its equilibrium position and then back. © the disturbance continues down the slinky. © this disturbance that moves down the slinky is called a pulse. © if we keep “pulsing” the slinky back and forth, we could get a repeating disturbance. 24

Slinky Wave © This disturbance would look something like this © This type of wave is called a LONGITUDINAL wave. © The pulse is transferred through the medium of the slinky, but the slinky itself does not actually move. © It just displaces from its rest position and then returns to it. © So what really is being transferred? 25

Slinky Wave © Energy is being transferred. © The metal of the slinky is the MEDIUM in that transfers the energy pulse of the wave. © The medium ends up in the same place as it started … it just gets disturbed and then returns to it rest position. © The same thing can be seen with a stadium wave (think back to the stadium wave we made in class). 26

Longitudinal Wave © The wave we see here is a longitudinal wave. © The medium particles vibrate parallel to the motion of the pulse. © This is the same type of wave that we use to transfer sound. © How is sound made in your vocal cords and how does it gets to your ears? © show tuning fork demo 27

Transverse waves ©A second type of wave is a transverse wave. ©We said in a longitudinal wave the pulse travels in a direction parallel to the disturbance. ©In a transverse wave the pulse travels perpendicular to the disturbance. 28

Transverse Waves ©The differences between the two can be seen. List 2 differences… 29

Transverse Waves ©Transverse waves occur when we wiggle the slinky back and forth. ©They also occur when the source disturbance follows a periodic motion. ©A spring or a pendulum can accomplish this. ©The wave formed here is a SINE wave. © http: //webphysics. davidson. edu/course_material/py 130/demo/illustration 1 6_2. html 30

Swings and Springs © Describe 1 cycle of a pendulum swing © Describe 1 cycle of a spring “bounce” 31

Anatomy of a Wave ©Now we can begin to describe the anatomy of our waves. ©We will use a transverse wave to describe this since it is easier to see the pieces. 32

Anatomy of a Wave © In our wave here the dashed line represents the equilibrium position. © Once the medium is disturbed, it moves away from this position and then returns to it 33

Anatomy of a Wave crest ©The points A and F are called the CRESTS of the wave. ©This is the point where the wave exhibits the maximum amount of positive or upwards displacement 34

Anatomy of a Wave trough ©The points D and I are called the TROUGHS of the wave. ©These are the points where the wave exhibits maximum negative or downward displacement. 35

Anatomy of a Wave Amplitude ©The distance between the dashed line and point A is called the Amplitude of the wave. ©This is the maximum displacement that the wave moves away from its equilibrium. 36

Anatomy of a Wave wavelength © The distance between two consecutive similar points (in this case two crests) is called the wavelength. © This is the length of the wave pulse. © Between what other points is can a wavelength be measured? 37

Anatomy of a Wave ©What else can we determine? ©We know that things that repeat have a frequency and a period. How could we find a frequency and a period of a wave? What needs to be measured? 38

Wave frequency ©We know that frequency measure how often something happens over a certain amount of time. ©We can measure how many times a pulse passes a fixed point over a given amount of time, and this will give us the frequency. 39

Wave frequency measures how often something happens over a certain amount of time ©Suppose I wiggle a slinky back and forth, and count that 6 waves pass a point in 2 seconds. What would the frequency be? © 6 waves/2 seconds = 3 cycles / second © 3 Hz ©we use the term Hertz (Hz) to stand for cycles per second. 40

Wave Period ©The period describes the same thing as it did with a pendulum. ©It is the time it takes for one cycle to complete. ©It also is the reciprocal of the frequency. ©T = 1 / f ©f = 1 / T ©let’s see if you get it. 41

Wave Speed ©We can use what we know to determine how fast a wave is moving. ©What is the formula for velocity? ©velocity = distance / time ©What distance do we know about a wave ©wavelength ©and what time do we know ©period 42

Wave Speed ©so if we plug these in we get ©velocity = length of pulse / time for pulse to move pass a fixed point ©v = / T ©we will use the symbol (greek letter lambda) to represent wavelength 43

Wave Speed ©v = / T ©but what does T equal ©T = 1 / f ©so we can also write ©v = f ©velocity = frequency * wavelength ©This is known as the wave equation. ©examples 44

Wave Equation v=λf 1. ) Ocean waves 12 m in length strike a seawall with a frequency of 0. 5 Hz. How fast do these waves move? v=λf 2. ) sound waves traveling at 350 m/s are made by a tuning fork that vibrates 384 times each second. What is the wavelength of the sound waves produced? λ=v/f 3. ) The light rays from a laser pointer have a wavelength of 670 nm and travel at 300 Mm/s. What is the frequency of the source of these waves? f=v/λ 45

Wave Equation v=λ/T p 95 4. ) A nurse counts 76 heartbeats in one minute. What are the period and frequency of the hearts’ oscillations? f=vibrations/time period=1/f 5. ) New York’s 300 m tall Citicorp Tower oscillates in the wind with a period of 6. 80 s. Calculate its velocity of vibration. v=λ/T What is the frequency of the wave? f=v/λ 46

Wave Equation answers p 95 1. ) v=λf = 12/0. 5 = 6 m/s 2. ) λ=v/f = 350/384 = 0. 91 m 3. ) f=v/λ = 300/670 =0. 45 hz 4. ) f=vibrations/time = 76/60 =1. 27 hz period=1/f = 1/1. 27 = 0. 78 beats/sec 5. ) Calculate its velocity of vibration. v=λ/T = 300/6. 80 = 44. 23 m/s What is the frequency of the wave? f=v/λ = 44. 23/300 = 0. 14 hz 47

Wave model p 88 4. ) Waves are disturbances that travel through a medium ex: longitudinal sound waves 5. ) Only Electro. Magnetic (EM) waves can travel through a vacuum (empty space). Ex: transverse light waves. 6. ) Period = the time required for 1 cycle 7. ) Frequency = cycles/time =1/period f=1/T 8. ) Wave equation: wavelength λ=v/f or v =f λ 9. ) Waves transfer energy from one place to another. Large amplitude=large energy 48

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Introduction to Waves p 96 1. ) The following waves pass in 1 second. Mark one wavelength on each wave. What is their period and frequency? 52

More Wave model physics 10. Transverse waves have disturbances perpendicular to the wave direction. Light (and all other EM waves) are transverse. 11. Longitudinal waves have the disturbance in the same direction as the wave. All sounds are longitudinal (which is why you lose your hearing from loud sounds) 12. ) standing waves do not move. They are made of nodes and antinodes. 53 p 88

Quiz today! ©Turn in your Quiz when finished ©Finish Introduction to waves worksheet ©Phet: Finding Wave Properties (wave on a string simulation) NOT TODAY ©Turn in your notebook TODAY (because of the holiday Monday…) ©Extra credit available…. check the calendar 54 P 96 -97

Wave Behavior ©Now we know all about waves: ©How to describe them, measure them and analyze them. ©So let’s begin looking at some wave behaviors… 55

P 100 Free End ©One boundary type is when a wave’s medium is NOT attached to a stationary object as a free end. ©In this situation, the end of the medium is allowed to slide up and down. ©What would happen in this case? 56

Free End Animation 57

Free End ©Here the reflected pulse is not inverted. ©It is identical to the incident pulse, except it is moving in the opposite direction. ©The speed, wavelength, and amplitude are the same as the incident pulse. 58

Fixed End ©One type of boundary that a wave may encounter is that it may be attached to a fixed end. ©In this case, the end of the medium will not be able to move. ©What is going to happen if a wave pulse goes down this string and encounters the fixed end? 59

Fixed End Animation 60

Fixed End ©Here the incident pulse is an upward pulse. ©The reflected pulse is upside-down. It is inverted. ©The reflected pulse has the same speed, wavelength, and amplitude as the incident pulse. 61

Change in Medium ©Our third boundary condition is when the medium of a wave changes. ©Think of a thin rope attached to a thin rope. The point where the two ropes are attached is the boundary. ©At this point, a wave pulse will transfer from one medium to another. ©What will happen here? 62

Change in Medium Animation Test your understanding 63

Change in Medium © In this situation part of the wave is reflected, and part of the wave is transmitted. © Part of the wave energy is transferred to the more dense medium, and part is reflected. © The transmitted pulse is upright, while the reflected pulse is inverted. 64

Change in Medium ©The speed and wavelength of the reflected wave remain the same, but the amplitude decreases. ©The speed, wavelength, and amplitude of the transmitted pulse are all smaller than in the incident pulse. 65

Wave Interaction ©All we have left to discover is how waves interact with each other. ©When two waves meet while traveling along the same medium it is called INTERFERENCE. 66

Constructive Interference ©Let’s consider two waves moving towards each other, both having a positive upward amplitude. ©What will happen when they meet? 67

Constructive Interference ©They will ADD together to produce a greater amplitude. ©This is known as CONSTRUCTIVE INTERFERENCE. 68

Destructive Interference ©Now let’s consider the opposite, two waves moving towards each other, one having a positive (upward) and one a negative (downward) amplitude. ©What will happen when they meet? 69

Destructive Interference P 100 ©This time when they add together they will produce a smaller amplitude. ©This is know as DESTRUCTIVE INTERFERENCE. 70

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P 101 Bouncing Pulses ©Finish both sides ©Get a stamp 72

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Check Your Understanding p 85 P 101 © Which points will produce constructive interference and which will produce destructive interference? © Constructive ©G, J, M, N © Destructive ©H, I, K, L, O 76

Standing waves appear to be stationary (standing still) and the wave appears not to move. This is the result of wave interference between two waves. P 101 77

Resonance P 102 Resonance is a phenomena when the frequency of forced vibrations matches the objects natural frequency and this causes a dramatic increase in amplitude. © Break a glass © Watch the amazing "Gallopin' Gertie" November 7, 1940 film clip. Slender, elegant and graceful, the Tacoma Narrows Bridge stretched like a steel ribbon across Puget Sound in 1940. The third longest suspension span in the world opened on July 1 st. Only four months later, the great span's short life ended in disaster. Break a bridge 78

Examples of wave behavior ©Speaker waves with corn starch ©More speaker waves with corn starch ©Active noise control ©Beat (acoustics) ©Diffraction ©Double-slit experiment ©Thin film interference 79

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P 102 Finish and get a stamp 81

But how do they interact? Write a description and draw a picture for each behavior. A. Free end B. Fixed end C. Change in medium D. Constructive Interference E. Destructive Interference F. Standing waves G. Resonance P 99 -100 82

3 -2 -1 P 99 -100 ©Complete the following for your assigned wave behavior. We will share out to the class in 10 minutes. Use a whiteboard © 3 new things that you learned (definition, picture, example) © 2 new questions about waves © 1 connection to a previous activity ©Record each wave behavior in your notebook as presented 83

Moving sources p 103 ©What happens to sounds from a stationary source? ©What happens to sound when a Stationary source begins moving? ©What happens to sound as the source moves faster? 84

Doppler effect p 103 ©Describe the Doppler Effect 85

Moving sources ©Boat wakes ©Doppler effect 2 ©Doppler effect 3 ©Doppler at speed of sound ©Doppler at supersonic speeds ©Sonic boom ©***The Doppler Effect 86

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Waves review ©Quiz corrections ©Ch 26 cornell notes 10 points extra credit ©Extra credit due Monday 1/26 ©Finish CDP 25 -1 and CDP 25 -2 ©Finish Pto. Go (p 505 -507) 1 -6 today ©Get your work stamped before you go P 105 90

Investigation #3 (p 508 -510) Sounds in Strings Revisited P 106 © Draw the standing waves produced by the wave machines. Label wavelength(s), nodes, internodes © Go to the lab Length of string X 2=wavelength pitch bench to fill in the chart 1. ) What happens to the wavelength as you change the length of the string? 2. ) What happens to the pitch (frequency)? 3. ) What wave property changes to make the frequency higher? (hint: v =f λ and wave speed does not change!) ©Finish Pto. Go (p 505 -507) 1 -12 Get a stamp 91

Flame Organ p 107 ©Describe the apparatus/draw a picture ©Record your observations (at least 3) ©Apply a sound concept/principle/vocab word to this phenomena. Define the vocab word(s) and explain how the flame organ demonstrates this. ©A different view 92

Wave model p 88 13. ) The pitch of a sound corresponds to the frequency of vibration of the object producing the sound. The higher the pitch, the higher the frequency. 14. ) Decreasing the length of a vibrating string increases the frequency (pitch). 15. ) Increasing the tension on the string increases the frequency also 16. ) Wave velocity=frequency *wavelength 17. ) When the length of a vibrating string is decreased, the speed remains the same, so the frequency must increase (higher pitch sound) 93

P 107 -8 Finish… ©Do CDP 26 -1 ©READ p 511 -513 and answer CU (p 514) 1 -4 ©Answer Pto. Go (p 517) 1 -7 ©Get a stamp when finished Quiz Friday! 94

New project! Let Us Entertain You! p 109 ©Read Active Physics p 480 -481 and then look at the rest of the unit (p 482 -588) ©Watch the youtube clips Warm Wishes Campbell’s soup Blue Man Group 1 Blueman drumbone and wine glasses, Veggie orchestra, RC Car, project example 1, project example 2 ©In your notebook record 3 project ideas 3 questions about the project 3 sound principles that you might include 3 light special effects that you would like to use 95

Project plans ©Count off 1 -4 ©Make groups containing someone representing each number 1 -4 ©Share what you wrote on page 106 with your partners ©Each partner will record something on one of the whiteboards ©If you have something to add to another whiteboard, you may ©Light idea 96

Build your own musical instrument tutorials ©Build your own string instrument ©Build your own percussion ©Build your own woodwind ©Build your own brass 97

Benchmark #1: Build your own instrument p 110 ©Watch each tutorial (4 total) ©Build your own string instrument… ©Draw and label a picture of one instrument from EACH tutorial ©List the materials that are used ©Explain how each instrument makes at least 5 different notes (pitches) ©Summary: which instrument are you going to make? Explain your steps… 98

p 111 Portfolio entry #1 - Pitch ©Write what you KNOW about pitch 99

Portfolio entry #1 - Pitch p 111 Write what you KNOW about pitch Read about pitch (Active Physics page 486 -487) Add to your written response…In YOUR OWN WORDS! Did you use many physics words (frequency, transverse wave, wave length)? Use your RUBRIC. Do you have • Definition • Relationship (what happens to the pitch when frequency changes? ) • Musical instrument example • Great detail • Picture or diagram (label pictures of high and low pitch) Share out with a partner…partner, what score would you give this response? How can it be made better? Edit your response until it becomes a perfect 4!

Woodwind instruments ©Examples: pan flute, recorder ©Vibration made by forcing air across a thin edge ©Pitch changed when you use your fingers to plug holes in the length of the instrument (thus changing the length of the tube) 101

String instruments ©Examples: guitar, violin, harp ©Vibration made by plucking the strings (or drawing a bow across the strings) ©Pitch can be changed by either adjusting the tension in the strings, or changing the length of the strings 102

Percussion instruments ©Examples: bottle/glasses filled with water, pipes/tubes/wood pieces of various lengths (xylophone), drums (made from cardboard tubes) ©Vibration made by gently striking surface ©Pitch changed by having various lengths of substance (water, wood, cardboard) 103

Brass instruments ©Examples: trombone, flute, brass horn ©Vibrations made by forcing air through your lips ©Pitch changed by changing the length of the tube 104

4 season partners Spring- Fall- Winter- Summer- 105